Aeronautical propeller



R. w. DAVIS. \AERONYAUTICAL PROPELLER.

APPLICATION FILED JULY 17 Patented Aug. 2, 1921.

ATTORNEY UNITED STATES PATENT OFFICE.

AERONAUTICAL PROPELLER Specification of Letters Patent.

Patented Aug. 2, 1921.

Application filed July 17, 1918. Serial No. 245,347.

To all wizmit it may concern:

Be it known that I, Ronnnr WILLIAM DAVIS, a citizen of the UnitedStates, and a resident of Hiltonia, in the county of Essex and State ofNew Jersey, have invented certain new and useful Improvements inAeronautical Propellers, of which the following is a specification.

This invention relates to improvements in aeronautical propellers of thetype that are rotated to produce a translator-y movement of thestructure of which they form a part, and it appertains more particularlyto propellers adapted to exert a lifting or levitating effect upon thatkind of heavier-than-air apparatus known as helicopters.

One of the objects of the invention is to produce a propeller of theclass mentioned having smooth, stream line effects and comparativelylarge working surfaces or blades.

A further object is the production of a propeller of the type specified.capable of displacing large quantities of air at a rela tively lowrotative speed and with an economical expenditure of power.

Another object is to provide a propeller of the nature set forth wherelightness. strength and rigidity are attained with few and simple parts,adequately braced for useful and practical service and yet amenable tolow cost of production.

A still further object is the provision of a propeller of thecharacterdescribed composed of hollow members rotatively arranged toconduct away the exhaust gases from a combustion driving motor as wellas to direct the issuance thereof in a manner to prevent the air underthe blades from moving radially outward.

Still another object is so to form a propeller of the kind referred tothat the hot waste gases from the motor are utilized to prevent snow andice from finding a lodgment upon the blades thereof.

Other objects and advantages of the invention will become apparent asthe specification proceeds.

With the aforesaid objects in-view, the invention consists of the novelcombinations and arrangements of parts hereinafter described in theirpreferred embodiments,

ointed out in the subjoined claims, and illustrated on the annexeddrawings, where- Fig. III is a sectional view taken on the line III-IIIof Fig. II, in the direction po nted out by the arrows, parts beingomitted and other parts broken away to show the interior construction;

Fig. I" is a sectional view taken irregularly on the line IV-IV of Fig.I looking 1n the direction pointed out by the arrows;

Fig. V is a sectional view taken on the hne V- V of Fig. IV, looking ineither direction; and i Fig. VI is a fragmentary plan view of a detailshown in Figs. I, II and III.

In these views the numeral 1 designates a driving shaft, operated by acombustion Inotor (not shown) either directly or through intermediarygearing in any approved manner. 'Ihis shaft is preferably of steppedformation and includes a short reduced inner portion 2, a longer,further reduced middle portion 3, and a short still further reducedouter section 4.

Extending through the inner portions 1 and 2 of the said shaft is anaxial bore 5 communicating with a similar but smaller bore 6 runningthrough the outer portions 3 and 4.

A relatively large hub or inner carrier element 10 is rigidly affixedupon the shoaldered portion 2 of the shaft, while a smaller hub or outercarrier element 11 is likewise secured upon the outermost section 4. Apair of brackets 12 are formed with the said hub 10 and extend outwardlytherefrom in opposite directions. One side of these brackets may behollow to constitute conduits 13.

-The inner ends of the latter open into an annular chamber or recess 14in the hub 10, while the outer terminals of the said conduits lead intothe interior of sockets 15 at the extremities of the brackets. The saidrecess 14 communicates with ports 16 formed through the Wall of theportion 2 so as to afford a passage between the axial bore of the shaft,the recess, the conduits and the said sockets 15.

The hub element 10 is preferably secured to the portion 2 of the shaftby means of taper pins 18 which pass across the outer surfaces thereofand straddle the bore 5 in such a manner as to leave a clear passagethrough the same. The smaller hub 11 may be held to the outer section 4by a single taper pin 19, as indicated in Fig. I.

Rigidly supported in the sockets 15 are tubular members or arms 20arranged to extend tangentially outward in opposite directions andcommunicating endwise with the extremities of the conduits 13, so as toprovide a free passage therethrough. The ends of the sockets are tightlyclosed by plugs 21 to prevent the flow of air or gases.

Similar sockets 23 are formed on the opposite sides of the outer hub 11,although obviously the same could be made to pass centrally across thiselement. Theextremity of the shaft bore (5 has fitted therein a plug 24that shuts off all egress at that point.

The lower end ofthis plug is located immedlately above a recess 25 inthe said hub.

which recess communicates with the smaller bore 6 through ports 26formed in the portion 4.

Secured rigidly in the sockets 23 is another pair of hollow members orarms 27 which extend outwardly therefrom in opposite directions,tangentially but closely approaching the center of the shaft. The endsof the said arms within the sockets 23 are provided with openings 28that establish communication with the bore (3 through the, ports 26 andthe recess 25 hereinbefore referred to. The adjacent or inner ends-ofthe hollow arms 27 are closed by tight fitting plugs 29. The members 2O,27 are arranged in pairs or sets. with the individual members of eachpair or set disposed on lines parallel to one another. though runningoutwardly in opposite directions. However, the sets themselves are notin parallelism, but as clearly seen in Fig. I, they diverge to theextent that the lower and upper sets respectively occupy )lanesbisecting each other at an acute ang e.

Carried by the outer half of the tubular members 20 and 27 is aplurality of frames 33, 33, 33", and 33 which are curved substantiallyconcentric with the shaft and having each tapered end portions. Theseframes are composed of I-sections having each a central web and top andbottom flanges 34, the Webs of the different frames being perforated atexcept the innermost ones which are left imperforate. Thetapered'portions of the several frames are joined endwise by strips 36and 36 at the opposite upper and lower edges which constituterespectively the leading and trailing edges of the blades or wings ofthe propeller. The ends of the several frames, and the strips adjacentthereto, are arranged on lines substantially parallel to the members2(). 27, respectively.

The frames may be cast'of some such light metal as aluminum, or built upof strong wood or other suitable material, whereby lightness andstrength are attained. Enveloping all of the several members and frames,are thin, light coverings 37, made of any preferred substance such asmetal, textile fabric, or the like. The construction recited constitutesthe wings or blades of the propeller, which may be hollow or chamberedas described. Should it be desired to omit the hollow features of theblades it is only necessary to fasten a single sheet of metal to thebottom one of the flanges 34 of the said frames.

\Vithin the outer covering 37, the inwardly facing sides of the hollowarms 20 and 27 are provided with apertures 38 disposed in graduatednumbers along the Said sides. The major part of these apertures arelocated between the frames 33 and 33*, a lesser number between theframes 33 and 33", and still fewer between the outer pairs of frames 33and 33. The outermost frames 33" are shown as provided either withstraight radially disposed apertures 35, at the extreme right handportions of Figs. I and II, or with right angular (apertures 33!) formedthrough the bottom flange 34 of-the said outer frame. ()ne portion ofthe latter 'named apertures extends parallel to the axis of the shaft 1or at substantially right angles to the blade of the propeller. Both theapertures 3:") and 39 are disposed at or near the outer perimetral edgesof the blades, transversely thereof. The escaping gases issue throughthese axially arranged apertures and form a curtain which acts as abarrier adapted to reduce if not entirely obviate such radial outwardmotion of the air as may occur under the propeller blades. As indicatedin Fig. IV the gases enter the blades oppositely at different levels.

The means for holding the frames 33, 33 etc., to the arms 20, 27 areshown in Figs. I and II as consisting of wire lacing 40 and throughrivets 41, either or both of which may be used.

A clamp ring 42 is fixed in an annular groove 42 formed in the shaft 1at a specified distance below the lower carrier element 10. This ring isprovided with ears or lugs 43 from which extend pairs of guys 44 and4:"). The guys 44 have their outer terminals attached to eyes 46 securedto the under sides of the blades at the juncture of the frames 33 withthe arms 27, at a point about two-thirds the distance outwardly of thelength of the propeller blades near the leading edges thereof.

neeaaae and distance out on the wings but adjacent to the trailing edgesthereof. From the eyes last named extend other guys 48, diverging in aplane at right angles to the axis of the shaft 1, to the sockets 15.

From the foregoing it will be seen the front or leading edges of theblades are arranged approximately radial and move squarely against theair in a circular path, thereby producing the least friction against theblades as well as reducing the sidewise vor lateral slip of the airunder the same.

The difference in pitch is attained by having the upper arms 27 closelydisposed adjacent to the center'of "the shaft while the lower arms 20are considerably offset therefrom.

It will be noted that the lower arms 20 which are subjected tocompression strain The upper arms 27 which are primarily exposed tobending strains are guyed to the inner portion of the shaft in the samemanner as the arms 20, namely, axially and below the same, but with thedifference that in this case the guys 44 are behind the arms.

The strains on all of these members are arranged to be transmitted bythe several pairs of guys 44, 45 and 48 inwardly-of the shaft as closeas possible to its point of support. The pushing strain from the arms 20is carried to the arms 27 by the frames 33, 33*, etc, and produces alifting stress on the latter arms which in turn is taken care of by thesaid guys 44.

The exhaust gases from the internal combustion motor which drives thepropeller, may enter the hollow shaft endwise thereof, or can beadmitted through apertures 51, formed in the sides of the shaft 1, Fig.III. Surrounding these apertures is a sleeve 52 that may also serve as abearing, and to which a pipe 53 leading from the motor outlet isconnected. Direct communication is thereby had with the alined bores 55,6, ports 16, 2G, recesses 14, 25, conduits 13, openings 28, hollow arms20, 27. and internal and external apertures 38 and 39, respectively.

The utilization of the heat from the motor exhaust within the blades ofthe propeller first, prevents snow and ice from lodging thereon; second.induces a scavenging .action upon the said exhaust; and thirdly,

as before mentioned, tends to minimize the outward sllp of the air underthe wings.

While a certain preferred embodiment of this device has been shown anddescribed, it will be understood that changes in the form, arrangements,proportions and details thereof may be made, without departing from thescope of the invention as defined by the appended claims.

Having described my invention what I desire to secure by Letters Patentand claim, is

1. A motor driven aeronautical propeller comprising a plurality ofblades, and means for conveying waste gases from the motor to saidblades and causing them to issue transversely thereof, whereby the gasesact as a barrier against the radialfiow of the air under the blades.

2. A motor driven aeronautical propeller comprising plural blades, andmeans for leading the exhaust gases from the motor to issue arcuatelyadjacent to the outer edges of said blades so as to minimize the outwardslip of the air thereunder.

3. A motor driven aeronautical propeller comprising blades, and meansextending at different levels relatively to said blades for passing theproducts of combustion from the motor to the perimetral edges thereof,said means being provided at substantially right angles to said edgeswith orifices through which said gases are caused to issue.

4. A motor driven aeronautical propeller comprising one or more blades,and means for heating the same by conducting in proximity thereto theburnt gases from the motor. said means enabling the gases to issuecircumferentially of the blade or blades whereby the rotary motion ofthe latter creates a drawing action tending to scavenge the motor.

5. A motor driven aeronautical propeller comprising a hollow shaftconnected with the exhaust from the motor, tubular members communicatingwith said shaft, and opposed blades on said members acted upon by theburnt gases during their discharge.

6. A motor driven aeronautical propeller comprising a hollow shaftadapted to receive the exhaust gases from the motor, tubular memberscommunicating With said shaft and provided with perforations at theirouter ends, and chambered blades carried by said members taking overtheir perforated portions and having orifices for the discharge of thegases.

7. A motor driven aeronautical'propeller comprising a hollow shaftadapted to receive the exhaust gases from the motor, recessed elementscarried in spaced relation upon said shaft, and communicating with theinterior thereof, tubular members supported by said elements incommunication with the recesses in the latter. and chambered bladesincluding discharge orifices, said blades being mounted upon the outerends of said members, said ends of the members having perforationsenabling the gases to pass into said blades in advance of their exitthrough the orifices.

8. An aeronautical propeller including a shaft, elements mounted inspaced relation on the latter, arms held in pairs by said elements atdifferent distances from said shaft, and opposed blades supported uponthe outer portions of said arms.

.9. An aeronautical propeller'inoluding a shaft having spaced lower andupper portions of different sizes, an element formed with carriersoffset from said shaft, said element being affixed to the lower portionof the latter, another element provided with carriers fixed to the upperportion of the shaft adjacent to the axis thereof, arms extending inopposite directions from the carriers of both said elements, and opposedblades joining the upper with the lower ones of said arms.

10. An aeronautical propeller including a shaft, lower and upperelements mounted in spaced relation on the latter, sockets formed Withsaid elements at different distances from said shaft, the sockets on thelower element being offset from the shaft while the sockets on the upperelement are located adjacent to the axis thereof, sets of arms extendingin opposite directions from the sockets of both elements, and opposedblades joining the lower with the upper sets of said arms.

11. An aeronautical propeller including a shaft, lower and upperelements spaced axially on the latter, pairs of arms extending inopposite directions from said elements, the lower pair of said armsbeing offset substantially tangentially to said shaft while the upperarmspass closely to the axis thereof, and opposed blades joining thelower with the upper pairs of arms.

12. An aeronautical propeller including a shaft, opposed blades carriedfrom the latter, said blades having leading and trailing edges disposedsubstantially diametral to and tangentially offset from said shaftrespectively, and guys extending convergingly from said blades to theshaft and also at right angles thereto.

13. An aeronautical propeller including a shaft, lower and uppercarriers spaced upon the latter, pairs of arms projecting tangentiallyoutward from said carriers 1n supported in tangential, relation bopposite directions, the lower pair of said arms being offset from saidshaft while the upper pair is adjacent to the axis thereof. opposedblades supported by said pairs of arms, and guys extending from saidblades to a point on the shaft downwardly beneath the lower carrier andalso to the outer portions of the carrier last named.

14. An aeronautical propeller including a shaft, lower and uppercarriers spaced axially thereupon, sockets formed with said carriers,the sockets on the lower carrier being offset from said shaft while thesockets on the upper carrier are disposed adjacent thereto, armsprojecting tangentially outward from said sockets in opposite direc.tions, opposed blades mounted on said'arms, anchoring means fastened tothe shaft be neath the lower carrier, and guys extending from said meansto the under side of said blades, some of said guys converging forwardfrom their respective points of attachment on the lower portions of theblades downwardly to the anchoring means, other guys running from thesame points of attachment horizontally forward to the sockets of thelower carriers, and certain other guys converging from the upperportions of the blades downwardly to the anchoring means in a rearward"direction.

15. vAn aeronautical propeller including a shaft with shoulder portionsspaced apart from one end thereof, a carrier element secured upon theouter one of said portions. a larger carrier element attached to theinner shoulder portion, a .set of members the smaller element adjacentto said sha t, another set of members also held tangentially to thelatter at a distance therefrom by the larger element, and bladessustained conjointly by said members.

16. An aeronautical propeller including a shaft, a, set of membersextending tangen-. tially thereto in opposite directions, means forsupporting said members one on each side of said shaft at a distancetherefrom, a second set of members projecting oppositely from the shaft,other means on the latter carrying said second set of members diagonallyin offset relation to the first named set, and blades joining both setsof members.

ROBERT WILLIAM DAVIS.

